PROJ00116

• Contract/PO #: C153477
• Contractor Name: Victor, City of
• Water District: 0
• County: Teller
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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bottom width of 168 feet. The emergency spillway will have 2H:1V sideslopes and
a top width of 194 feet. This alternative is the same as Alternative #1 except
that the design flow is 1/2 of the PMF instead of the full PMF.

Modifications to the existing dam are the same as for Alternative #1 except that
the emergency spi 11 way wil 1 be 168 feet wide. Add it iona 1 embankment on the
downstream slope of the dam is required to provide stability Riprap replacement
is required on the upstream face and along the emergency spillway slope adjacent
to the dam. The concrete grade beam along the emergency spillway crest is also
required, although it will be much smaller due to the lesser spillway requirements.

Alternative 14 - Alternative #4 is the same as Alternative #2 except the modifica-
tions to the embankment and spillway are designed for 1/2 of the PMF instead of
the full PMF. Figure 5.6 presents the embankment modifications for this alterna-
tive. For Alternative #4, the embankment will be raised 5.5-feet and extended
along the downstream slope at 2.25H:1V to provide additional stability. The
proposed emergency spillway will have a bottom width of 42-feet and sideslopes of
2H:1V. The north slope adjacent to the dam embankment will be ripraped as well
as the upstream face of the dam. A concrete grade beam will be provided to
stabil ize the emergency spillway crest and to protect against erosion when the
spillway operates. As with Alternative #2, the 20-inch outlet decant pipe will
be extended to the toe of the new embankment section.

Each of the above alternatives was reviewed and prioritized based on a combination
of; estimated cost, dam and appurtenant structure safety, technical feasibil ity
and compliance with regulatory agency requirements. Ordinarily one of the major
cost factors in a dam is the design frequency and thus the size of the emergency
spillway. At present, the State Engineer requires that an embankment such as the
Victor No.2 be equipped with a spillway sized to pass the probable maximum flood
or size the spillway based on an incremental damage analysis. We have been
advised that the State Engineer is considering several hydrologic criteria for
inclusion in the rules and regulations for dam safety and that it is 1 ikely that
this revised criteria will give the City the option of downsizing the emergency
spillway to 1/2 the PMF and that further downsizing may be justified by an
incremental damage analysis. A cursory review of potential flood damages down-

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